/**
 * @param {number} n
 * @return {boolean}
 */
const isThree = function (n) {
  if (n == 1) return false
  let a = ~~Math.sqrt(n)
  if (n != a * a) return false
  for (let i = 2; i < a; i++) {
    if (n % i == 0) return false
  }
  return true
}
